(1) Field of the invention
The present invention relates to a tape extension device for a semiconductor producing apparatus and particularly to a tape extension device for a semiconductor producing apparatus which may average a tension force in two dimensions so as to extend the tape, and particularly to the semiconductor producing apparatus having such a tape extension device.
(2) (Prior Art)
In semiconductor producing processes, where a number of semiconductor chips are made by cutting a semiconductor wafer, prior to a cutting process, a tape is applied from a surface of the semiconductor wafer having a semiconductor connecting construction on another surface thereof, to a plate-like die frame which surrounds a periphery of the semiconductor wafer, in order to direct the semiconductor wafer precisely and simplify treatment of the semiconductor chips which are cut off from the semiconductor wafer.
As a method of applying the tape to the semiconductor wafer and the frame, for example, it uses such a method comprising the steps of tensing the tape above the semiconductor wafer and the plate-like frame surrounding the semiconductor wafer coaxially in order to prevent the tape from wrinkling, lifting the frame and the semiconductor wafer to the undersurface of the tape thereafter, pressing the tape onto the frame and the semiconductor wafer by means of for example a roller, and cutting off a part of the tape covering the frame and the semiconductor wafer.
For example, as shown in FIG. 5, the tape tension device for tensing the tape is arranged such that a fixed position roller and a movable roller 104 are positioned above a semiconductor wafer 101 and a frame 102 leaving a suitable distance in a down-web direction.
The fixed position roller and the movable roller 104 are positioned parallelly on the same level so as to be rotatable about a horizontal axis.
A counter roller 105 is arranged on an opposite side to the movable roller 104 of the fixed position roller 103 so as to be able to contact with and depart from the fixed position roller 103. A clamp pad 106 is arranged on an opposite side to the fixed position roller 104 of the movable roller 104 so as to be able to contact with and depart from the movable roller 104, and a drum roller 107, which is formed to have a small diameter at a middle portion thereof, is positioned above the fixed position roller 104.
The movable roller 104, the drum roller 107, the clamp pad 106 and a cylinder 108 for driving the clamp pad 106 are driven by means of a driving device 109 in a down-web direction, namely, a direction of transferring a tape 110 (the direction of flow of the tape).
The driving device 109 may sometimes be constructed by means of an air-cylinder, but in this case it is constructed as follows. In order to control a tension force of the tape 110 by adjusting an amount of movement of each of the moving roller 104 and the clamp pad 106, the moving roller 104 and the cylinder 108 are supported by a moving frame 111. The driving device 109 comprises a screw shaft 112 which is screwed into a screw hole formed with the moving frame 111 in such a state that the screw shaft is rotated and moved in the down-web direction, and a stepping motor 113 which drives the screw shaft 112.
The tape 110, which is drawn from a tape roll 114, goes through between the fixed position roller 103 and the counter roller 105, and then laterally goes from the underside of the fixed position roller 103 to the underside of the moving roller 104. Thereafter, the tape 110 goes through between the moving roller 104 and the clamp pad 106 and rides on the drum roller 107, and then the tape is wound on a winding roller 115.
The tape 110 is spread in a cross-web direction as it rides on the drum roller 107, so that the tape 110 can be extended on the semiconductor wafer and the frame 102 without wrinkles.
After suitable portions of the tape 110 are clamped by the fixed position roller 103 and the counter roller 105, the moving roller 104 and the clamp pad 106 clamp the tape 110. Then, the moving roller 104, the drum roller 107, the clamp pad 106 and the cylinder 108 are moved respectively for a predetermined distance in a direction which is remote from the fixed position roller 103, so that a tension force of for example 50.about.80 Kg. may be given to a part of the tape 110 between the fixed position roller 103 and the moving roller 104.
Thereafter, the semiconductor wafer 101 and the frame 102 are lifted and applied to the tape 110 and a part of the tape 110 covering the inner periphery of the frame 102 and the semiconductor wafer 110 is cut off, and then the semiconductor wafer 101 and the frame 102 having the tape 110 are moved downwards.
After the step, the counter roller 105 is separated from the fixed position roller 103 and the clamp pad 106 is also separated from the moving roller 104, and then the tape 110 is wound for a predetermined length while the moving roller 104 is returned to its original position.
Repeating a series of these steps, application of the tape 110 to the semiconductor wafer 101 and the frame 102 can be repeated in order.
According to the conventional tape extension device, the tension force in the cross-web direction given to the tape 110 by means of the drum roller 107 shares about 5% of the tension force in the down-web direction, which may just smooth away the tape 110.
When the semiconductor wafer 101 is cut off in a die-cutting process after the tape 110 is applied thereto, each of the intervals between semiconductor chips cut from the semiconductor wafer 101, becomes uneven. As the result, it becomes impossible to detect positions of the semiconductor chips when the semiconductor chips are peeled off from the tape 110 and removed by means of a pick-up machine. Therefore, it frequently happened that the pick-up machine is stopped automatically and its producing lines is interrupted.